GAPA NOTES
Important: These notes are not intended to replace the pilot’s manual for the PW-2. The manual should be studied before flying this airplane.
General Description
The PW-2 Gapa was designed at the Warsaw University of Technology and is the last in a series of primary trainers they designed there before moving on the higher performance designs of which the PW-5 is one.
The strut-braced wings are of composite construction with spars and D-tube of fiberglass, ribs from dense foam, and covered with Tedlar (a film similar to the mylar used to cover model airplanes, but about three times thicker). The wing struts are metal tubing covered with aerodynamic fiberglass fairings which double as the dive brakes, when rotated.
The fuselage is made of molded fiberglass. The control hookups use the same hardware as the PW-5 and the tow hook is the same Tost model used by almost all other European gliders. The main landing gear uses the same shock strut and geometry as that on the PW-5. The only brake for ground operations is the metal nose skid that is cushioned with rubber donuts.
Anyone flying the Gapa at the club should be at least checked out in the 1-26, PW-5, or similar ship, and also be checked out to fly in the rear seat of the 2-33. The single seat ships will acquaint the pilot with the increased pitch sensitivity of most single seat sailplanes. The reason for rear seat time in the 2-33 is due to the fact that the PW-2 has horrible upward visibility similar, but worse, to the back seat of the 2-33. At least the 2-33 has an overhead window and you can lean forward and peek around the leading edge for a better view if you have to. In the Gapa there is no window or clear view panel above the pilot and due to the reclined seating position leaning forward to peek around the leading edge is impossible. In fact once seated and strapped in (on?) you cannot reach the instrument panel unless you happen to be an orangutan or similar simian. The visibility everywhere but upwards is terrific. The fuselage behind the pilot’s head is only about a foot wide so looking behind you is no problem.
These recommendations are not meant to imply that the Gapa is difficult to fly. It was, after all, designed as a primary training glider and does not have a mean bone in its airframe or any surprises other than a rather steep glideslope. It is well designed and constructed and a blast to fly.
You should not even think of flying the Gapa without safety glasses or goggles. The tow plane will kick up lots of dust and even small pebbles on takeoff. You may be able to hold your breath during this phase of the launch but you certainly don’t want to be holding your eyes closed. Actually this is one ship where you will be thankful for any crosswind since it will blow the dust away from you during most of the launch. Goggles with a good strap are preferred to safety glasses since you will be able to turn your head to the side and even look behind you without the slipstream trying to yank them from your face. Eye protection will also keep your eyes from watering during a short flight or drying out during a long flight.
Dress for the conditions. Even if it is a hundred degrees on the ground I still wear a long sleeve winter weight shirt and long pants while flying the Gapa. In any season other than summer you need to layer your upper body and if the conditions are good for a high altitude gain you need to make sure your ears and face are protected. At 10,000 feet in March, sitting in a 40-knot wind is pretty chilly (understatement). Also, if you are dressed comfortably you will be much more likely to actually move your head and look around you instead of sitting there like a turtle in its shell. The floppy hat that is the favorite of soaring pilots is not needed while flying the Gapa due to shade provided by the leading edge of the wing. Not to mention the problem of keeping one of those things on your head while towing at 60 knots. In cold or moderate weather a knit ski hat seems to work best. It will stay on your head and keep your ears warm. The type of ski hat with a facemask is also ideal to keep your nose warm. Basically, when it is cold do not leave any skin exposed to the wind. You will fly, and scan for traffic better, if you are comfortable.
At any time other than the summer you should be wearing gloves with gauntlets that go over the cuffs of you coat. It is also not a bad idea to wear light-weight gloves in the summer just to keep the sun of your hands.
Pre-Take Off
The pre flight inspection is very simple due to the fact that most of the control hardware is external and easy to inspect.
The Gapa cockpit was designed with the use of a parachute in mind and no one seems argue about wearing one will flying it. The seat area of the fuselage is smooth, painted fiberglass with a raised lip around the sides. The seat belt and shoulder straps are the same design as those on the PW-5. Once you are seated, sit back and tighten every thing firmly. The belts are released by pulling the release strap that in the air looks much like all the other straps. It is better not to be fussing with them while flying. If you try to adjust the belts once your in the air there is a chance you could pull the release strap by mistake, which would not much of an issue in your average sailplane but can add considerable excitement to your life while flying “on” an open cockpit glider. Make sure the altimeter is set before you strap in because it will be impossible to do so later, unless your genetic make up is very different from the average pilot.
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Do not attempt to launch the Gapa without a wing runner. The angle that it sits on the ground combined with the soft aluminum tip skids create too much drag for a safe launch. If the plane yaws too much on launch you will probably bend one of the tip skids as you head for the edge of the runway.
For low time pilots the Gapa might seem a little pitch sensitive on take off (about the same as the 1-26). You will appreciate any cross wind since it will blow the dust from the tow plane away from you. If there is no crosswind hold your breath if you have to but resist the temptation to close your eyes or to fly higher than normal to avoid the dust before the towplane lifts off.
During my first few take offs I kept my left hand on the tow release just incase things got out of hand. I now know the Gapa tracks very well during takeoff but it is still a good idea to keep your hand resting on the release since it is not in the standard position as in most gliders. Like the most Schweizers, you need to lift the nose skid off of the ground but there is no tendency to tip back on the tailskid during the initial acceleration. Be prepared to lift off much sooner than any thing else you have flown.
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Tow
The Gapa handles very well on tow. The tow pilot should not fly more than 60 knots with 55 being preferable. Loyal can tow at 55 knots with the stock C150 but 60 is about the slowest he can tow with the re-engined Aerobat. There is no pitch trim but the stick forces are so low that it is never a problem.
One thing I have noticed is that steering the towplane by moving out to the side is not very effective, probably due to the fact that the Gapa just doesn’t tug on tail hard enough for the tow pilot to notice.
Control coordination in the Gapa is very similar to the PW-5. Both designs have fairly small rudder areas and require a lot of rudder during the turns. The rudder pedals are basically steel tubes with a small area of contact with your feet. After a couple of hours in the air I find that they start to become irritating since I wear soft soled shoes when flying. Other than the rudder pedals I find the Gapa quit comfortable during long flights and how many sailplanes have you flown where you can stretch your legs during flight by sticking them outside the cockpit. As already mentioned the stick force is light throughout the speed range so the lack of trim is not a problem. I have found the ailerons to have plenty of authority, even in strong 10+ knot thermals.
This is a great ship for dissecting thermal structure. With a very low wing loading it reacts to every nuance in a thermal and with no canopy, or windshield, you will feel all of the wind shifts within the thermal. You will also be more in-tune with the temperature changes while entering and exiting thermals. There is also no such thing as a “stick thermal” while flying the Gapa. Due to its high drag and low inertia when you pull back on the stick all you do is slow down, there is not much energy to trade for altitude. Be careful while thermaling in a gaggle. Since you can get right in the core of the thermal and work every little gust it is possible to outclimb the other ships making the lack of upward visibility a big problem. Just be even more vigilant than normal and consider staying away from the gaggle if you not sure who the other pilots are and their level of experience. The last thing you want is for someone to cross the core without you being able to see them making the shift.
The manual states that the best glide ratio is about 12.5/1 and that feels about right. Now remember, hang glider pilots routinely go out on long cross-country flights with lower performing equipment, so don’t sit there and say the Gapa can’t be used for going somewhere. My longest flight so far was a triangle totaling close to 50 miles. Of course I got over 10,000 MSL that day so I darn well better have tried for some distance. Just because you have the glide ratio of a Cessna 152 doesn’t mean you can’t soar. Every thing just happens steeper, that’s all.
The stall on the Gapa is a non-event. It stalls about like a 2-33 with two people on board. With full aft stick about all it will do is mush along at somewhere under 30 knots.
The airbrakes are a very clever design. The fairings on the wing struts rotate about 80°, leading edge down, at full deployment. Not only do they present a good amount of area to the air stream but the their lift vector points downward when you use them. There is no buffeting or noise when they are being used so you really wonder if they are doing much until you are near the ground and then you can see just how effective they are.
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When setting up for your landings you should fly a tighter pattern than you probably are used to and use 45 to 50 knots throughout the pattern. I am usually no more than 100 yards outboard of the runway while flying on the downwind leg. When landing on runway 13 or runway 7 I usually cross the fence at about 400’. Yes, it seems really high and I know you will probably use the airbrakes the first couple of times. I am sure someone will hike down the runway to help retrieve you. The tail boom places the tail very high so you can actually use much more flare just before touching down than most sailplanes will allow. With the low speed, and low inertia the rollout is very short. Off field landings will be a piece of cake with the Gapa.
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Well, there you have it. The Gapa has a lot to offer. It will teach you things about thermals that you might not notice in other sailplanes. There is nothing like sitting right out there when a golden eagle or a hawk is flying off of your wing. Think of the lower performance as a challenge and not something to shy away from. Consider it lifting weights for a cross-country pilot. The 2-33 and 1-26 will seem positively high-performance after flying the Gapa. The main reason to fly it is because it is just so darn fun and it may take quit awhile for the “Gapa Grin” to leave your face after landing.
If you have any questions that I may not have addressed here feel free to ask me about them.
Green Air,
Jonathan Pitt
